Many businesses have enterprise telephone networks, wherein each terminal is associated with a private directory number and sometimes a public directory number. The private directory numbers can be used to call from terminal to terminal within the enterprise telephone network, even when the respective terminals are in different corporate locations. Accordingly, the need to dial area codes or other prefixes is avoided. For callers outside of the enterprise telephone network, the caller must use the public directory numbers associated with the terminals or a common enterprise number and an extension number. Use of the private directory numbers by those outside of the enterprise is generally futile, as the Public Switched Telephone Network (PSTN) will not recognize the private directory numbers.
Given the proliferation of cellular communication, many employees rely on their cellular telephones to communicate with other employees. In many instances, these employees need to use their cellular telephones to call terminals within the enterprise telephone network. When doing so, the public directory numbers associated with the enterprise terminals must be used. These public directory numbers may need to be dialed with an appropriate area code in certain cases. As such, the employees who use cellular telephones often need to keep track of and use different public and private directory numbers depending on whether they are in the office or traveling. As the number of contacts increases, keeping track of multiple numbers for a single person or terminal becomes difficult to manage.
Cellular telephone users are also unable to initiate calls to many voice over packet (VoP) terminals having Internet Protocol (IP), Session Initiation Protocol (SIP), or other packet network addresses, whether they are associated with a private enterprise telephone network or not. Accordingly, there is a need for a way to initiate calls from cellular terminals using private directory numbers. There is a further need to initiate calls to packet network addresses using a cellular terminal from a traditional cellular interface.